truck failed smog check - suggestions?

You had better start checking your bank account.

EGR valve not working?

HC at idle means you should probably do a tune up and your air filter might be dirty. I'd clean up the throttle body. More than likely it's all gunked up. I'd change the PCV valve as well.

The NOx could be carbon build up, a bad EGR valve or a catalytic converter going out. The cat-con will also cause your HC's to be higher. You should go ahead and list all the readings so we can see what the rest of the readings were to give us a better chance at diagnosing your problem.

Your HC's are not all that bad. It could also be timing related. The NOx looks like it was maxed out. I'd put my bet on the EGR. Under load, the EGR valve is supposed to open up and reduce the NOx emissions.

-Bruce

High HC: Too lean by just a bit. NOxides also supports too lean diag. Possible bad O2 sensor would be easiest to fix. A slightly leaking EGR would also cause this. Replace EGR. Test O2 sensor by monitoring voltage while giving spritz of throttle-body cleaner into throttle body (make sure cleaner does not come in contact with MAF parts!). If O2 sensor output doesn't change radically or the output does not settle, it's bad.

- Bill